The progress of technologies boosts the development of the industry of home electric appliance. Many electric appliances employ digital technology to realize intellectualized control such that the traditional electric appliance is added a controller chip, which executes relevant programs to perform functions of the appliance. The extended electric appliance is also referred to as “the smart electric appliance”. As a popular interface technology, USB (Universal Serial Bus) interface is added to the smart electric appliance by manufacturers to communicate between the smart electric appliance and USB ready external devices. For example, the USB port on digital TV can be used to connect USB disks or removable hard disks to view pictures or play audio or video contents.
The requirements of features and security for the electric appliance also increase. For example, the owner of an electric appliance may want to control who can use or how one can use the electric appliance, i.e. to control the rights to use the appliance. In particular, parents may want to restrict the TV programs deemed not suitable for their children to watch, the period of time that the TV can be used by their children, or the channels that are allowed or disallowed to be watched by their children.
The key device is a two-factor security authentication device with a USB interface in information security sector. It is an easy-to-use and low-cost security solution. With built-in SCM or smart card chip, it can store user's keys or digital certificates. The cryptographic algorithms reside on the key device for authenticating the user. The key device provides many security features, such as email encryption, digital signature, secure certificates, secure website logon, and access to SSL secured websites. It is impossible for a user's private key to be transferred from the key device. Also, the key device integrates with physical anti-attack protection. If the key device is used for the access control of the smart electric appliance, a low-cost solution to the security problems of use of the smart electric appliance is formed by taking advantage of an existing technology, while fully modifying the architecture of the smart electric appliance is avoided.
Some abbreviations are used in description of the present invention. The term “VID” refers to “Vendor ID”, which is an identifier of the manufacturer who produces the key device. The term “PID” refers to “Product ID, which is a product serial number identifier of a product (the key device).